argument

In her book, Critical Thinking: An Appeal To Reason, Peg Tittle has an interesting and useful way of organizing 15 logical fallacies. Simply put, they’re all irrelevant to the assessment of whether an argument is true or not. Using Tittle’s guidelines, we can quickly sort out what we need to pay attention to and what we can safely ignore.

Though these fallacies are irrelevant to truth, they are very relevant to persuasion. Critical thinking is about discovering the truth; it’s about the present and the past. Persuasion is about the future, where truth has yet to be established. Critical thinking helps us decide what we can be certain of. Persuasion helps us make good choices when we’re uncertain. Critical thinking is about truth; persuasion is about choice. What’s poison to one is often catnip to the other.

With that thought in mind, let’s take a look at Tittle’s 15 irrelevant fallacies. If someone tosses one of these at you in a debate, your response is simple: “That’s irrelevant.”

Ad hominem: character– the person who created the argument is evil; therefore the argument is unacceptable. (Or the reverse).

Ad hominem: tu quoque– the person making the argument doesn’t practice what she preaches. You say, it’s wrong to hunt but you eat meat.

Ad hominem: poisoning the well— the person making the argument has something to gain. He’s not disinterested. Before you listen to my opponent, I would like to remind you that he stands to profit handsomely if you approve this proposal.

Genetic fallacy– considering the origin, not the argument. The idea came to you in a dream. That’s not acceptable.

Inappropriate standard: common practice – just because everybody’s doing it doesn’t make it true. Appeals to inertia and status quo.Example: most people peel bananas from the “wrong” end.

Inappropriate standard: moderation/extreme – claims that an argument is true (or false) because it is too extreme (or too moderate). AKA the Fallacy of the Golden Mean.

Appeal to popularity: bandwagon effect– just because an idea is popular doesn’t make it true. Often found in ads.

Appeal to popularity: elites – only a few can make the grade or be admitted. Many are called; few are chosen.

Two wrongs –our competitors have cheated, therefore, it’s acceptable for us to cheat.

Going off topic: straw man or paper tiger– misrepresenting the other side. Responding to an argument that is not the argument presented.

Going off topic: red herring – a false scent that leads the argument astray. Person 1: We shouldn’t do that. Person 2: If we don’t do it, someone else will.

Going off topic: non sequitir – making a statement that doesn’t follow logically from its antecedents. Person 1: We should feed the poor. Person 2: You’re a communist.

Appeals to emotion– incorporating emotions to assess truth rather than using logic. You say we should kill millions of chickens to stop the avian flu. That’s disgusting.

Chances are that you’ve used some of these fallacies in a debate or argument. Indeed, you may have convinced someone to choose X rather than Y using them. Though these fallacies may be persuasive, it’s useful to remember that they have nothing to do with truth.

Let’s talk about logic for a moment. When you hear the word argument, you may think of a heated exchange of opinions. It’s emotional and angry. A logician would call this a quarrel rather than an argument. In the world of logic, an argument means that you offer reasons to support a conclusion.

An argument can be valid or invalid and sound or unsound. Here’s an example of an argument in a classic form:

Premise 1: All women have freckles.

Premise 2: Suellen is a woman.

Conclusion: Suellen has freckles.

We have two reasons that lead us to a conclusion. In other words, it’s an argument. Is it a good argument? Well, that’s a different question.

Let’s look first at validity. An argument is valid if the conclusion flows logically from the premises. In this case, we have a major premise and a minor premise and – if they are true – the conclusion is inescapable. Suellen must have freckles. The conclusion flows logically from the premises. The argument is valid.

But is the argument sound? An argument is sound if the premises are verifiably true. The second premise is verifiably true – Suellen is indeed a woman. But the first premise is not verifiably true. All we have to do is look around. We’ll quickly realize that the first premise is false – not all women have freckles.

So, the argument is valid but unsound. One of the premises that leads to the conclusion is false. Can we safely assume, then, that the conclusion is also false? Not so fast, bub.

This is what’s known as the fallacy of fallacies. We often assume that, if there’s a fallacy in an argument, then the conclusion must necessarily be false. Not so. It means the conclusion is not proven. The fact that something is not proven doesn’t necessarily mean that it’s false. (Indeed, in technical terms, we’ve never proven that smoking causes cancer in humans).

Our example demonstrates the fallacy of fallacies. We agree that the argument is valid but not sound. One of the premises is false. Yet, if you know Suellen, you know that the conclusion is true. She does indeed have freckles. So even an unsound (or invalid) argument can result in a conclusion that’s true.

What’s the moral here? There’s a big difference between not proven and not true. Something that’s not proven may well be true. That’s when you want to consider Pascal’s Wager.

Let’s say you’re having an argument and your opponent has stated his position clearly. You’d like to persuade him to change his position. But you’re working against the consistency principle — once your opponent has stated a position, inertia keeps him from changing it. Your argument needs to be clear and compelling but it also needs to provide a way for your opponent to change positions gracefully. While it may be tempting, making your opponent feel small or cornered is usually unsuccessful. Remember, you’re interested in persuading, not humiliating. Similarly, making your argument overly abstract doesn’t do much good. You need to get personal and stay positive. Learn more in the video.

This tip has a lot to do with the consistency principle — and how to overcome it. You can find more on the consistency principle here.